I love the colors and build quality.
But my old SMC-A 24/2,8 has better micro resolution and lower distorsion.
But they are both great lenses.
As all Zeiss T* lenses it has very high contrast which many confuses with
resolution.It is NOT the same thing.I prefer the higher resolution than high contrast.

I have acquired two other Zeiss lenses in the past (the older Contax 28 and 85). I acquired this lens because, the older Contax Carl Zeiss 25mm f2.8 Distagon T* was the same price, before modifying the mount from C/Y to the K mount.

Essentially I was looking for something a bit wider than 28 mm, with the distortion very well controlled. This lens hit on all of the categories.

Build – All metal and glass - well the lens cover is plastic, as is the rear cap. Extremely well built (you will never find a better built lens), machined ribbed metal on the barrel focus ring (equivalent and waaaaay beyond the Pentax FA Limited build quality). The build quality is also beyond that of the Contax lenses (by Carl Zeiss). The focus (to twist) is backwards from Pentax – however, I have not had any problems adapting to this. From minimum focus distance to infinity is about 95% or 355 degrees of a full turn. Very very smooth focusing, with wonderful damping. Aperture setting, click at full f stops, with the "A" mode. Filter size is 67mm and with a full metal lens hood standard.

Size – The lens is certainly not a compact (pancake) lens, however it is larger than the FA 31 Ltd, in all dimensions, height, diameter and about double the weight. The physical size and weight is also significantly greater than the Contax lens of the same focal length and aperture. The lens does weigh a ton, it does have the feel of a lot of heft - or mass to it, however it is well balanced on my K5 body.

Optics – A full frame lens, all glass and absolutely superb in every respect. The lens is fully multi-coated using Zeiss’ T* coatings, one of the best available, the coatings are optimized for digital, flare is virtually non existent.

Sharpness – It will be extremely difficult (nearly impossible) to find a lens that is sharper than this one - in the center. Actually the entire Carl Zeiss line of lenses are noted for their sharpness. This is sharp from f2.8 - wide open and just gets sharper. f4 to f5.6 is optimum for resolution and the sharpness is extremely wonderful.

Performance – I was shooting this lens side by side with the FA 31 Ltd. The Zeiss consistently tends to overexpose slightly - 1/2 to 2/3 of a stop.

Flare – Non existent and I have shot directly into sunsets

Bokeh – Extremely nice. This may be the lens' hidden secret. The aperture is only f2.8, however it is able to close focus to 6 inches and with 180 of the 355 degrees of the focus throw is from 6 to 12 inches. This provides a very thin depth of field plane, and the foreground and background out of focus areas can be controlled very well. The bokeh is very nice (to my eyes), pretty creamy and contrasty.

Colors and Contrast– Extremely nice. The Zeiss character is very evident in the colors and contrastness of the lens.

Price – Zeiss has discontinued this lens in the Pentax K mount - since Pentax does not have a full frame camera and this is a full frame lens. The prices of these lenses vary, since they are available new only on the close out and used market, via ebay, craigslist, and the other usual used avenues of acquisition. I found the price range to be very wide - almost double. Some shopping should yield results. All of that said - they are still expensive.

This lens reports to the body as a "A" lens, however you need to manually set the focal length to 24 (since 25 is not an option on Pentax bodies). The lens does provide auto aperture - in the "A" setting. It does not self identify as a Zeiss lens - leaves the EXIF field blank.

Others reviews have indicated some field curvature and vignetting on full frame bodies. On a cropped sensor body and in my shooting, I have not seen any, I was not looking for any either. I was looking for landscapes, cityscapes, and some semi macro shooting with the best optics I could find. For the price, I guess you could say it should be perfect, however its up to the photographer.

Is it a 10? - No and neither is it a 9. I would put it at 9+ or around 9.25 to 9.5. So, with that - since I have no choice, I'll round it to a 9, primary due to the price - and it would have been really nice for the lens to self report aperture and "Zeiss" to the body.